Telethermometer.



No. s3e,as4 Patented Nov. [4, I899. a. F. ATwoon.

TELETHERMOMETER.

(Application filed Aug. 17, 1899.)

(No Model.)

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' I BY ATTORNEYS mz Nonms PETERS cu. PMo'ro-umov, WASHINGTON uv n.

UNITED STATES GEORGE F. ATVVOOD, OF ORANGE, NEW JERSEY, ASSIGNOR TO SCHAEFFER 85 BUDENBERG, OF NEW YORK, N. Y.

TELETHERMOMETER.

SPECIFICATION formingpart of Letters Patent No. 636,884, dated November 14, 1899.

Application fild A u t 1 7 189 9.

To all whom it may concern.-

Be it known that I, GEORGE F. ATWOOD, a citizen of theUnited States,residingat Orange, in the county of Essex and State of New Jersey, have invented new and useful Improvements in Gages or Measuring Instruments, of which the following is a specification.

By means of this invention an instrument such as a thermometer, pressure-gage, and the like can be made to register or give its notations without being affected by the surrounding temperature, so that accuracy or reliability is secured.

This invention is set forth in the following specification and claims and illustrated in the annexed drawings, in Which- Figure 1 is a plan view of the instrument. Fig. 2 is a side elevation of the springs, with index-actuator. Fig. 3 is an edge View of the index-actuator sectioned along 3 3,Fig. 2. Fig. 4 is a View of the springs on larger scale than in Fig. 1. Fig. 5 is a section along 5 5, Fig. 2. Fig. 6 is a detail View of the bulb.

The device shown is a recording-thermometer, although the invention is not confined to such instrument. The dial or record-sheet 1 can be kept rotating or moving by clockwork, or the like, and the index or hand 3, when made to mark on the dial, produces a record. The index or hand 3, or its base part 3, swings or fulcrums at 4 and is connected or linked at 5 to what may be called an index-actuator 6. The actuator 6 is shown in the form of abail or yoke-shaped frame swinging about the point or pivot 7. A lever or equalizingbar 8 is connected or fulcrumed at 9 to actuator 6. This bar 8, as seen at Fig. 3, is con nected by links 10 and 11 to the springs 12 and 14, respectively. These springs, being oppositely wound or differential springs, will act as a compensator or form means for neutralizing the eifects of the temperature surrounding the instrument, as presently explained. These springs are hollow coiled springs. Spring12communicateswithatube 15, which enters or communicates with the foot-piece or bulb 16, Figs. 1 and 6. Spring 14 communicates with a tube 17, which stops short of or does not communicate with the interior of foot-piece or bulb 16. For convenience the free or closed end of tube 17 can be Serial No. 727,554. (No model.)

secured to the foot-piece or bulb, so as not to fly about loose or be in the way; but, as already stated, this tube 17 while confined to the foot-piece does not enter or communicate with its interior. The springs 12 and 14, with tubes 15 and 17 and foot-piece 16, are filled with a suitable liquid'say alcohol. The footpiece or bulb 16 is applied to or inserted into a locality-as, for example, a cold-storage space'the temperature of which is to be ascertained. The rise and fall of temperature in this space causes the liquid in foot-piece 16 to expand or contract, and the varying pressure resulting in tube 15 and spring 12 causes the latter to tend more or less to a straight position, and thereby move the link 10, with bar 8 and pivot 9, so as to cause ac tuator 6 to move and actuate the index 3.

The temperature surrounding the instru* ment or the tube 15 and spring 12 may of course vary from the temperature to which the foot-piece or bulb 16 is exposed. Say this surrounding or intermediate temperature is higher than the temperature at the foot-piece or bulb 16 and tends to expand the fluid in tube 15 and spring 12 more than required to note the temperature of such point. This surrounding or disturbing temperature at the same time acts on tube 17 and counterspring 14. The two counter-springs 12 and 14 tending to move the links 10 and 11 of lever 8 in opposite directions cause this lever or bar to swing idly about pivot 9 or to swing without moving the actuator 6 and hand 3. These oppositely-wound springs 12 and 14 thus form a compensator or neutralize one another as regards the temperature surrounding these springs 12 and 14 with tubes 15 and 17.

The invention is of course not necessarily confined to thermometers, as it can be elsewhere utilized-say in pyrometers, manometers, and other instruments.

The device can be modified. It is, for example, not necessary to use the lever or bar 8, as the opposing springs 12 and 14 can be connected to actuator 6 without this bar, but the device shown has been found serviceable in practice. By neutralizing the temperature effects between the foot-piece 16 and the spring 12 an accurate instrument is obtained.

The tubes and 17 are both exposed or subject to equal influences between the footpiece or bulb 16 and the springs, so as to properly or simultaneously actuate said neutralizing-springs. The springs can be formed spiral or with a number of coils or a so-called Bourdon spring with but one coil or turn can be used.

The index 3 is practically formed of two pieces, the part 3 being secured or adj ustably fastened to part 3, which last-named part fulcrums or swings on or about pivot 4.

lVhat I claim as new, and desire to secure by Letters Patent, is-

1. The combination of a movable index, two reversely expanding and contracting tubular springs, a swinging bail or frame connected with the index, and devices connecting said bail or frame with the two springs, substantially as described.

2. The combination of a recording-index, two reversely-movable tubular springs,a movable frame connected with and operating the index, devices connecting the movable frame with the reversely-movable springs, a hollow foot-piece or bulb, and two tubes communieating respectively with said springs and one of which communicates with the foot-piece or bulb, substantially as described.

3. A thermometer or the like having a bulb,

an index, and a compensator formed by oppositely-wound or differential springs substantially as described.

4. The combination of a recording-index, two reversely-movable tubular springs, a swinging bail oryoke-shaped frame connected with and operating the index, devices connecting said frame with said springs, a hollow foot-piece or bulb, and two tubes communicating with the tubular springs and one of GEORGE F. AT \VOOD.

Viinesses:

W. O. HAUFF, E. F. KASTENHUBER. 

